An Optimization for Split Delivery Open Vehicle Routing Problem with Manual Materials Handling

This paper considers the open vehicle routing problem (OVRP) where goods are manually unloaded at customers by delivery workers who have been pre-assigned to vehicles. Since the split delivery demonstrated that it could reduce the cost by allowing to split each delivery into different vehicles. Thus, OVRP with split delivery (OVRPSD) is addressed. Initially, a mathematical model of the OVRPSD is formulated. Its objective is to minimize the total cost that consisting of total fixed cost of vehicles and delivery workers and total transportation cost. At customer locations, goods must be manually unloaded by delivery workers who are preassigned to vehicles. For safety, the total physical workload imposed on any worker must not exceed the worker's working physical capacity. A numerical example is presented and solved using an ILOG CPLEX optimization tool. The optimal result shows that the model can be solved to a minimum total cost that prevents excessive energy expenditure of delivery workers.